2.5V LOW POWER
PRECISION REFERENCE SOURCE
ISSUE 1 - OCTOBER 1995
DEVICE DESCRIPTION
The ZRT025 is a monolithic integrated circuit
providing a precise stable reference voltage
of 2.5V at 500µA.
The circuit features a knee current of 150µA
and operation over a wide range of
temperatures and currents.
The ZRT025 is available in a 3-pin metal can
package for through hole applications as
well as SOT223 and SO8 packages for
surface mount applications. Each package
option offers a trim facility whereby the
output voltage can be adjusted as shown in
F i g . 1. Thi s f a ci l i t y i s u sed w he n
compensating for system errors or setting
the reference output to a particular value.
When the trim facility is not used, the pin
should be left open circuit.
ZRT025
FEATURES
•
•
•
•
•
•
•
•
•
•
Trimmable output
Excellent temperature stability
Low output noise figure
Available in two temperature ranges
1 and 2% initial voltage tolerance
versions available
No external stabilising capacitor
required in most cases
Low slope resistance
No derating required at low
temperatures
TO18 package
SOT223 and SO8 small outline
packages
SCHEMATIC DIAGRAM
R
V
CC
V
R
R=V
CC
-V
R
I
R
R
T
=100k
(Optional trim facility)
G
nd
G
nd
This circuit will allow the reference to be
trimmed over a wide range. The device is
specified over a 5% trim range.
4-279
ZRT025
ABSOLUTE MAXIMUM RATING
Reverse Current
Operating Temperature
A grade
C grade
Storage Temperature
TO18
SO8, SOT223
75mA ø
-55°C to 125°C
0°C to 70°C
-55 °C to 175 °C
-55 °C to 125 °C
Power Dissipation (T
amb
=25°C)
TO18
300mW
SO8
625mW
SOT223
2W
ø Above 72°C this figure should be linearly
derated to 25mA at 125°C
TEMPERATURE DEPENDENT ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
INITIAL
GRADE A
VOLTAGE -55°C TO 125°C
TOLERANCE
TYP
MAX
%
1&2
6.8
22.5
GRADE C
0°C TO 70°C
TYP
2.7
MAX
8.8
mV
UNITS
V
R
Output voltage change
over relevant
temperature range
(See note (a))
Output voltage
temperature coefficient
(See note (b))
T
C
V
R
1&2
15.0
50.0
15.0
50.0
ppm/°C
ELECTRICAL CHARACTERISTICS
( at T
amb
=25°C and Trim pin o/c unless otherwise stated)
SYMBOL
V
R
PARAMETER
Output voltage
1% tolerance (A1,C1)
2% tolerance (C2)
Output voltage adjustment
range
MIN.
TYP.
MAX. UNITS
2.525 V
2.550
%
ppm/°C/%
75
10
0.3
50
0.85
2.0
mA
µs
µV
Ω
R
L
=1kΩ
Peak to peak
measurement
I
R
= 0.5mA to
5mA
See note (c)
COMMENTS
2.475 2.500
2.450 2.500
5
2.5
0.15
I
R
=500µA
R
T
=100kΩ
V
TRIM
T
C
V
TRIM
Change in T
C
V
R
with output
adjustment
I
R
t
on
t
off
e
np-p
R
S
Operating current range
Turn-on time
Turn-off time
Output voltage noise (over the
range 0.1 to 10Hz)
Slope resistance
4-280
ZRT025
TYPICAL CHARACTERISTICS
NOTES
(a)
Output change with temperature
The absolute maximum difference between
the maximum output voltage and the
minimum output voltage over the specified
temperature range
(c) Slope resistance (R
S
)
The slope resistance is defined as :
R
S
=
change
in
V
R
specifiedcurrentrange
∆
I = 5 - 0.5 = 4.5mA (typically)
(d) Line regulation
The ratio of change in output voltage to the
change in input voltage producing it.
V
R
= V
max
- V
min
(b) Output temperature coefficient (T
C
V
R
)
The ratio of the output change with
temperature to the specified temperature
range expressed in ppm/°C
R
S
x
100
%
⁄
V
V
R
x
R
source
T
c
V
R
=
∆
V
R
x
10
6
ppm
⁄
°C
V
R
x
∆
T
∆T=
Full temperature range
4-281
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